Hi,
On 18.04.2016 00:44, Sakari Ailus wrote:
Hi Ivaylo,
On Sat, Apr 16, 2016 at 11:12:20AM +0300, Ivaylo Dimitrov wrote:
Some sensors (like the one in Nokia N900) provide metadata in the first
couple of lines. Make that information information available to the
pipeline.
Signed-off-by: Ivaylo Dimitrov <ivo.g.dimitrov.75@xxxxxxxxx>
---
drivers/media/i2c/smiapp/smiapp-core.c | 12 ++++++++++++
drivers/media/i2c/smiapp/smiapp.h | 1 +
2 files changed, 13 insertions(+)
...
I'm afraid I think this is not exactly the best way to approach the issue.
It'd work, somehow, yes, but ---
1. A compliant sensor (at least in theory) is able to tell this information
itself. The number of metadata lines is present in the sensor frame format
descriptors.
Right. And this is where that number is taken from in the patch and made
available to whoever wants to use it. See
http://lxr.free-electrons.com/source/drivers/media/i2c/smiapp/smiapp-core.c#L177
. I don't really understand your point here. Maybe the patch description
is fuzzy? Could you elaborate?
2. The more generic problem of describing the frame layout should be solved.
Sensor metadata is just a special case of this. I've proposed frame
descriptors (see an old RFC
<URL:http://www.spinics.net/lists/linux-media/msg67295.html>), but this is
just a partial solution as well; the APIs would need to be extended to
support metadata capture (I think Laurent has been working on that).
Could be, however what we have right now is
http://lxr.free-electrons.com/source/drivers/media/platform/omap3isp/ispccp2.c#L369.
Also, the patch is not trying to solve the problem with frame format
description(or anything in general), but a mere way to pass an already
available information in the sensor which is needed by omap3isp, by
using an already existing API. I don't see how's that related to the way
v4l API going to evolve in some (distant?) future. Not to say that once
those frame format descriptors are available, it should be relatively
easy to simply remove g_skip_top_lines form v4l2_subdev_sensor_ops and
fix the drivers to use the new API.
BTW if you have any idea on how to pass (or set) the number of lines to
be skipped at the start of the frame to omap3isp driver in some other
way, I am fine with dropping the $subject patch and sending another one
implementing your proposal.
Regards,
Ivo
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